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Dr. Alessandro Giardini
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The ductus arteriosus is not a defect. It is a vessel every baby has before birth. it represents a deliberate shortcut between the aorta and the pulmonary artery that allows the foetal circulation to work without using the lungs, which are not needed in the womb. At birth, when the baby takes a first breath and lung pressure drops, the ductus normally closes within a day or two. In most children, that is the end of the story.
When it stays open (or remains patent, in the clinical sense) it becomes a patent ductus arteriosus, or PDA. Whether that requires any treatment at all depends on several things: how large the opening is, how the heart is responding, whether symptoms are present, and the age of the child. Many PDAs will never need intervention. Some will close with observation alone. A minority require active treatment.
Understanding the difference matters, because the decision to intervene is never automatic.
A small PDA produces no significant shunting of blood. The amount of extra flow returning to the lungs is trivial, the heart does not have to work harder, and the child is entirely well. These are sometimes called silent or haemodynamically insignificant PDAs, and they are often detected incidentally during an echocardiogram performed for an unrelated reason. In many cases, no treatment is needed and no follow-up is required beyond a single review.
Larger PDAs are different. When blood shunts through a significant opening, it takes a circular detour: from the aorta, back into the pulmonary artery, through the lungs again, and back to the left side of the heart. The left ventricle has to handle this extra volume. Over time, the heart enlarges and the pulmonary vessels, the blood vessels in the lungs, are exposed to abnormally high pressure and flow. That is when things become clinically important.
Dr Giardini's assessment focuses on whether the PDA is exerting a measurable effect on the heart. The echocardiogram is the key investigation. It can measure the size of the ductus, estimate the direction and volume of shunting, assess the dimensions of the heart chambers, and look at pulmonary pressures.
A PDA is more likely to require closure when any of the following are present:
- The left ventricle is dilated. When the left heart is carrying excess volume load, its dimensions increase. This is one of the clearest markers that the PDA is significant.
- Pulmonary pressure is elevated. Prolonged exposure to high flow in the lung arteries raises the pulmonary vascular resistance. This is a time-sensitive concern as if left long enough, the rise in pulmonary pressure can become irreversible.
- Symptoms are present. A baby who feeds poorly, gains weight slowly, sweats during feeds, or breathes fast and hard is a baby whose heart is working harder than it should. In older children, reduced exercise tolerance or recurrent chest infections can be linked to a significant left-to-right shunt.
- The PDA is large and has not shown signs of reducing. Unlike some VSDs, a moderate to large PDA in a full-term infant is unlikely to close spontaneously.
- Endocarditis risk (an infection of the heart structures) is a consideration too. When a child has a PDA and the PDA is associated with a typical heart murmur then there is a recommendation to close it as the PDA increases the risk of the child developing a serious infection of the PDA itself if germs are able to enter the blood circulation. This condition is uncommon but serious and is called bacterial endocarditis. The evidence is that in these children with a PDA and an audible murmur the risk of PDA closure is smaller then the risk of developing infective endocarditis and therefore closure is recommended.
For the vast majority of children beyond infancy, closure is performed as a catheter procedure. A thin tube is passed from the groin vein up to the heart, and a small plug or coil device is deployed directly into the ductus. The procedure takes under an hour in most cases, requires no chest incision, and children typically go home the following day. Success rates are very high.
In premature newborns, the situation is different. The ductus in preterm babies often responds to indomethacin or ibuprofen which drugs that help it constrict and close by blocking the prostaglandins that keep it open. This medical approach only works in the newborn period and is not effective in full-term infants or older children.
Surgery in the form of tying or clipping the ductus through a small incision between the ribs is now reserved for cases where catheter closure is not technically feasible, usually because the PDA is very large or has an unusual anatomy. It remains a safe and effective operation with excellent long-term results.
This is one of the more common anxious moments in paediatric cardiology: a child has an echo for palpitations or an innocent murmur, and a small PDA is found incidentally. Dr Giardini reassures families that a genuinely tiny PDA causing no haemodynamic disturbance and no audible murmur is very unlikely to cause any problems. Most centres would see the child once or twice to confirm it is not growing and not affecting the heart, and then discharge with no further follow-up required. The use of antibiotic prophylaxis for endocarditis in this group has been largely abandoned in UK practice in recent years.
That said, every PDA is different, and the decision must always be based on the full clinical picture rather than a single measurement.
Once a PDA is successfully closed, whether by catheter or surgery, the circulation normalises promptly. The extra volume load on the left heart resolves, and the heart typically remodels back toward normal dimensions over the following months. Long-term follow-up is not generally required unless there are other cardiac concerns. Children return to full activity. There are no lasting restrictions.
The outcome after PDA closure in otherwise healthy children is excellent, and most families can be reassured that this is one of the more straightforward interventions in paediatric cardiology.
Not always. Many PDAs in premature babies close without any intervention once the baby is more mature and stable. The neonatology and cardiology teams will monitor closely and only recommend treatment, with medication first, and then catheter or surgery if needed if the PDA is causing measurable problems with breathing, feeding, or cardiovascular stability. A significant number of premature babies with a PDA do very well without active closure.
A six-month review for a small PDA is very reassuring. This means the team is confident the ductus is not causing harm right now and is giving it time to potentially close on its own or confirm its insignificance. If the PDA were causing a problem, the plan would not be to wait. Dr Giardini recommends using that interval to ask specific questions at the next appointment: has the size changed? Is the heart responding? Is any intervention being considered?
There is no single right age. If a PDA is significant and causing haemodynamic effects, Dr Giardini would generally recommend closure as soon as the child is big enough for the catheter procedure, often from around six months of age depending on weight and anatomy. For children in whom a PDA is found later in childhood incidentally, closure can be planned as an elective procedure at any age.
For the great majority of children, the answer is no. Catheter closure is the standard approach and does not require any chest incision or general surgery in the traditional sense. Open surgery is only used when the catheter approach is not possible due to the anatomy of the ductus.
This is exceedingly rare. Once a device is in place and the PDA has sealed, the risk of recanalisation is extremely low. Dr Giardini discusses residual shunting at the post-procedure echocardiogram and will confirm closure at the follow-up review.
Almost certainly not, if the PDA is small. Palpitations in children most commonly arise from normal sinus variation, benign ectopic beats, or anxiety — none of which have any connection to a small PDA. The discovery of the PDA is incidental. Dr Giardini's evaluation would focus on both findings independently to give a full picture.
Author: Dr. Alessandro Giardini, MD, PhD, Consultant Paediatric Cardiologist
Written 06/06/2026